Yup, entirely Photoshop. To tell the truth, I don't really remember *how* I did it, this was one of my first works with Photoshop/digital arts. But I'm pretty sure I used the "Add noise" filter + blur, smudge, multiply, overlay, overlay, overlay and some "Bleach" filter inside a photo editing plugin for Photoshop called "Nik Color Effects" (I applied that one at least 5 times).

I think I even made a pattern for the brushed feeling, but I really can't remember, sorry :/